Results are expressed as picograms per lung (means SEM). to vaccinate Aim2- and Nlrp3-deficient (and mutant of the live vaccine strain (LVS). The results demonstrate that this innate immune responses in and mice vaccinated with the mutant Metoclopramide HCl differ from those of their wild-type Metoclopramide HCl counterparts. However, despite these differences in the innate immune responses, both and mice are fully guarded against an intranasal lethal challenge dose of LVS. Moreover, the lack of both Aim2 and Nlrp3 inflammasome sensors does not affect the production of vaccination-induced antibody and cell-mediated Metoclopramide HCl responses. Overall, this study reports a novel finding that both Aim2 and Nlrp3 Metoclopramide HCl are dispensable for vaccination-induced immunity against respiratory tularemia caused by is usually a nonmotile, facultative, intracellular, Gram-negative bacterium that causes a fatal disease known as tularemia. Strains of subsp. (also known as type A strains) are remarkably virulent. Due to its extremely high virulence, ease of spread by aerosolization, and potential to be used as a bioterror agent, is usually classified by the CDC as a tier 1 category A select agent (1). Strains of subsp. (also known as type B strains), although responsible for causing illness in healthy individuals throughout the Northern Hemisphere, are relatively less virulent than type A strains (2). can cause contamination in a broad range Metoclopramide HCl of hosts and can survive in contaminated water, soil, or vegetation. is usually transmitted to humans or between animals through bites of infected arthropod vectors, direct contact with infected animal tissues, consumption of contaminated food or water, and inhalation of infective aerosols (3). Clinical presentation includes ulceroglandular, glandular, oculoglandular, oropharyngeal, and pneumonic forms of tularemia and depends on the route of contamination, virulence, and dose of the infecting subspecies (1, 4). The other two subspecies of subsp. and subsp. subsp. LVS shows a high degree of sequence homology and a very similar life cycle to type A strains. However, LVS is usually attenuated for virulence in humans and therefore is used as a surrogate for highly virulent type A strains in research laboratories to study the virulence mechanisms of strain. On the other hand, previous studies have shown that in LVS-infected macrophages, the activation of the inflammasome is usually delayed, and the induction of IL-1 is very low (13, 14). The inability of the type A SchuS4 strain to induce inflammation early during contamination is like LVS, with a weaker induction of inflammasome activation (15). However, the role of Nlrp3 in innate immune responses to is not fully established. Nlrp3 has been shown to mediate an inflammasome-independent function in response to contamination that is detrimental to the host (16). Several studies provide strong evidence for a significant role played by inflammasome-dependent cytokines in shaping adaptive immune responses (13, 17,C21). The inflammasome-mediated cytokine IL-1 is required for T helper type 17 (Th17) differentiation, while IL-18 amplifies the production of interferon gamma (IFN-), a Th1-polarizing cytokine (22,C24). However, contributions of both the AIM2 and NLRP3 inflammasomes to the development of vaccine-induced adaptive immune responses against are not known. EmrA1 encoded by the gene of is usually a transmembrane component of the multidrug efflux pumps belonging to the Emr type major Rabbit Polyclonal to GPR19 facilitator superfamily of transporters. The mutant of LVS is usually sensitive to oxidative stress and antibiotics and is attenuated for intramacrophage growth and virulence in mice (25). The oxidant sensitivity of the mutant is due to its failure to secrete the antioxidant enzymes superoxide dismutase B (SodB) and catalase (KatG). In a previous study, we tested the vaccine potential of the mutant in the prevention of respiratory tularemia. We reported that this mutant could be safely administered at a very high dose via the intranasal route without any adverse effects on vaccinated mice. Moreover, mutant-vaccinated mice are guarded against 1,000 to 10,000 100% lethal doses (LD100s) of LVS, and the mutant provides partial protection against respiratory challenge with the virulent SchuS4 strain in vaccinated C57BL/6 mice (26). Based on these features, in this study, we used the mutant to immunize and mice to determine the contributions of Aim2 and Nlrp3 inflammasomes to vaccine-induced immune responses against respiratory tularemia caused by LVS. RESULTS Similar to wild-type mice, the mutant is usually attenuated for virulence in and mice. Both and mice vary in their susceptibilities to primary respiratory contamination caused by wild-type LVS, with the former being more susceptible and the latter being.